Ladder rails have been made with slots which are linear or straight, as shown in FIG. 1. The bolt holding the ladder shoe to the rail extends through the ladder shoe through the slot. Typically, the rail may rotate slightly within the ladder shoe with the bolt sliding down a slot until the edge of the rail contacts or is interfered with by the ladder shoe, as shown in FIG. 2. If the ladder rail is continued to be pivoted or rotated without the rail being lifted off of the ladder shoe foot so the bolt slides to the bottom of the slot, then the entire shoe is caused to be pivoted or rotated with the rail, as shown in FIG. 3. This causes the stable base the shoe affords the ladder to be lost since the ladder shoe is now basically resting on its edge.
An attempt to overcome this problem of the shoe rotating with the rail as the rail is pivoted, unless the rail is lifted relative to the shoe, is found in U.S. Pat. No. 5,154,255 of Werner Co. which discloses a ladder shoe with a curved slot. As the ladder rail rotates relative to the ladder shoe with the curved slot, the rotation essentially corresponds with the curvature of the slot and the ladder rail is allowed to pivot along the slot relative to the shoe so the shoe or the slot do not interfere with the movement of the rail. Typically, a shoe that contains a curved slot must be made larger than others to contain the curved slot.
The present invention involves a non-linear or curved slot which is cut into the rail instead of the shoe. Putting the curved slot in the rail allows for a smaller, lighter weight and cheaper shoe.